Rho associated protein kinases (ROCKs) are Ser/Thr protein kinases, activated by small GTPases of the Rho family that act as molecular switches to mediate cell signaling. The Rho/ROCK signaling pathway is known to participate in the regulation of numerous cellular functions such as actin cytoskeleton organization, contraction, cell adhesion, motility, morphology, proliferation, cytokinesis, gene expression, and angiogenesis.
Two isoforms, ROCK1 and ROCK2, have been identified sharing 64% and 79% overall sequence identity and similarity respectively and 92% identity and 97% similarity in their kinase domains. The two isoforms have been found to possess differential tissue distribution. ROCK1 is expressed in lung, liver, stomach, spleen, kidney and testis, whereas ROCK2 is highly expressed in brain, heart and muscle tissues (Nakagawa, et al., FEBS Lett, 1996, 392:189-193). Despite the differential tissue distribution, little is known about the functional differences between the two ROCK isoforms (Sapet, et al., Blood, 2006, 108:1868-1876; Chang, et al., Proc Natl Acad Sci USA, 2006, 103:14495-14500; Sebbagh, et al., Nat Cell Biol, 2001, 3:346-352; Thumkeo, et al., Mol Cell Biol, 2003, 23:5043-55; Shimizu, et al., J Cell Biol, 2005, 168:941-53; Zhang, et al., Faseb J, 2006, 20:916-925; Rikitake, et al., Circulation, 2005, 112:2959-2965; Coleman, et al., Nat Cell Biol, 2001, 3:339-45; Sebbagh, et al., J Exp Med, 2005, 201:465-471).
ROCKs have been subjected to growing attention, having been implicated in a range of therapeutic areas including cardiovascular diseases (Shimokawa, et al., Trends Pharmacol Sci, 2007, 28:296-302; Xing, et al., Drug News Perspect, 2006, 19:517-522; Liao, et al., J Cardiovasc Pharmacol, 2007, 50:17-24; Shimokawa, et al., Arterioscler Thromb Vasc Biol, 2005, 25:1767-1775; Dong, et al., Cardiovasc Hematol Agents Med Chem, 2009, 7:322-330), CNS disorders (Kubo, et al., Recent Pat CNS Drug Discov, 2007, 2:173-9; Kubo, et al., Ther Clin Risk Manage, 2008, 4:605-615), inflammation (LoGrasso Philip, et al., Curr Top Med Chem, 2009, 9:704-23), and cancer (Suwa, et al., Br J Cancer, 1998, 77:147-152; Kamai, et al., Clinical Cancer Research, 2004, 10:4799-4805; Schmitz, et al., Exp Cell Res, 2000, 261:1-12; Imamura, et al., Jpn J Cancer Res, 2000, 91:811-816; Somlyo, et al., Biochem Biophys Res Commun, 2000, 269:652-659; Uchida, et al., Biochem Biophys Res Commun, 2000, 269:633-640; Itoh, et al., Nat Med (NY), 1999, 5:221-225; Uehata, et al., Nature, 1997, 389:990-4; Ishizaki, et al., Mol Pharmacol, 2000, 57:976-983; Narumiya, et al., Methods Enzymol, 2000, 325:273-84; Nakajima, et al., “Cancer Chemother Pharmacol, 2003a, 52:319-24; Nakajima, et al., Eur J Pharmacol, 2003b, 459:113-20; Ying, et al., Mol Cancer Ther, 2006, 5:2158-2164; Somlyo, et al., Faseb J, 2003, 17:223-234; Hampson, et al., Br J Cancer, 2009, 101:829-839; Igishi, et al., Int J Oncol, 2003, 23:1079-1085; Liu, et al., Cancer Res, 2009, 69:8742-8751; Ogata, et al., Int J Gynecol Cancer, 2009, 19:1473-80; Zohrabian, et al., Anticancer Res, 2009, 29:119-123).
Cooverexpression of Rho and ROCK proteins in cancer cells has been reported in ovarian cancer, pancreatic, testicular, and bladder cancer (Suwa et al. (1998); Kamai et al. (2004)). Metastasis requires changes in the migratory, invasivee and adhesive properties of tumor cells. These processes which depend on the proper assembly/disassembly of actincytoskeleton are regulated by Rho/ROCK pathway and play an important role in the development and progression of cancer (Schmitz et al. (2000)). The implication of Rho/ROCK signalling pathway in invasion by tumor cells (Imamura et al. (2000); Somlyo et al. (2000)), angiogenesis (Uchida et al. (2000)), and their evolution to metastasis (Itoh et al. (1999)) has been amply documented. In light of these findings, the pharmacological inhibition of ROCKs has been suggested as a promising strategy in the prevention of cell invasion, a central event in the process of metastasis (Itoh et al. (1999); Uehata et al. (1997); Ishizaki et al. (2000); Narumiya et al. (2000)).
The potential of ROCK inhibitors as anticancer agents was demonstrated by the identification of ATP competitive inhibitors, Y27632 (1), and Wf536 (2) (FIG. 1) (Itoh et al. (1999); Nakajima et al. (2003a); Nakajima et al. (2003b); Somlyo et al. (2000)). Specifically, 1 was reported to reduce metastasis in animal model systems (Itoh et al. (1999)), and 2 has shown efficacy in preventing tumor metastasis in vivo models by inhibiting tumor-induced angiogenesis as well as tumor motility (Nakajima et al. (2003a); Nakajima et al. (2003b); Somlyo et al. (2003)). Han and coworkers have also investigated the ability of Fasudil (3) (5-(1,4-diazepane-1-sulfonyl)isoquinoline) (the only ROCK inhibitor clinically approved in Japan for the treatment of cerebral vasospasm) to inhibit progression of human and rat tumors in animal models (Ying et al. (2006)).
Significant research efforts have been directed towards the identification of more potent and more selective ROCK inhibitors (Chen, et al., Bioorg. Med. Chem. Lett., 2008, 18:6406-6409; Sessions, et al., Bioorg. Med. Chem. Lett., 2008, 18:6390-6393; Iwakubo, et al., Bioorg. Med. Chem., 2007, 15:1022-1033; Goodman, et al., J. Med. Chem., 2007, 50:6-9; Feng, et al., J. Med. Chem., 2008, 51:6642-6645; Sehon, et al., J. Med. Chem., 2008, 51:6631-6634) including isoquinolinamines (Ray, J et al., Bioorg. Med. Chem. Lett., 2011, 21:97-101; Ray, et al., Bioorg. Med. Chem. Lett., 2011, 21:1084-1088), triazines (Ho, et al., Bioorg. Med. Chem. Lett., 2009, 19:6027-6031), isoquinolinones (Bosanac, et al., Bioorg. Med. Chem. Lett., 2010, 20:3746-3749; Ginn, et al., Bioorg. Med. Chem. Lett., 2010, 20:5153-5156), quinazolinones (Fang, et al., Bioorg. Med. Chem. Lett., 2011, 21:1844-1848), benzothiazoles (Yin, et al., Bioorg. Med. Chem. Lett., 2009, 19:6686-6690) and diaminopyrazines (Henderson, et al., Bioorg. Med. Chem. Lett., 2010, 20:1137-1140) and their use for the treatment of cardiovascular diseases and CNS disorders. The antitumor and antimetastatic properties of these inhibitors has yet to be shown or published.
The aminothiazole derivative CID5056270 (4)(FIG. 2) has been reported (Feng, et al., J. Med. Chem., 2008, 51:6642-6645) to potently inhibit ROCK2 enzymatic activity with an IC50 values <3 nM. It displayed high potency in (FRET)-based Z'-Lyte biological assay (Kang, et al., Bioorg. Med. Chem. Lett., 2009, 19:533-537; Koresawa, et al., Assay Drug Dev. Technol., 2004, 2:153-160) (ROCK2 IC50 0.56 nM) and also inhibited ROCK1 with an IC50 of 13 nM (FIG. 2). In view of its potency against both ROCK isoforms and selectivity over Aurora-A (IC50>100 μM) (FIG. 2), 4 has been a starting point for the design of ROCK inhibitors. Specifically, several pyridylthiazole ureas, such as 5a, have been synthesized and tested as ROCK inhibitors (WO 2011/130740). While many of these compounds were highly potent, further inhibitors are still needed. Disclosed herein are compounds and methods that address these and other needs.